steppers and current

I have a question about the current that i run my steppers at.
I used to have a stepperworld controller and when i used it the steppers ran pretty hot. after i switched to geckos they barely get warm.

so, my question is. am i running them way too low? i believe that i have the calculations for the resistors correct, but seeing that people say that they need heatsinks on their steppers makes me wonder.. are steppers supposed to run hot when they run at the correct voltage?

thanks,
magnus